In gel electrophoresis apparatuses known so far, the gels are received either vertically or horizontally, i.e. the gels either stand upright in the gel electrophoresis apparatuses or lie horizontally in the gel electrophoresis apparatuses. Usually, the necessary electrophoresis buffer is provided from two connecting liquid tanks or buffer containers, thus for a vertical gel an upper and a lower buffer container.
A disadvantage of receiving a gel in a gel cassette vertically in a gel electrophoresis apparatus is that the working position for the person who loads the gel with samples is very uncomfortable in that the refraction of light in the glass plates of the gel cassette makes it very difficult to clearly see the gel edge without placing one's eyes closely by the gel cassette at the same time as the pipette with which the wells are loaded, has to be brought up above eye-level in order for the samples to be applied in a correct manner into the wells without the pipette tip contacting and damaging the gel. Neither is it possible to instead look at the gel edge straight from above through the liquid surface in the upper buffer container to which the gel cassette is connected, since the vertical position of the pipette tip in relation to the gel edge can then not be determined.
The disadvantage of horizontally mounted gels is that present systems for loading of samples restrict the resolution which is the reason why horizontal systems cannot be used when a high resolution is required.
EP-A-339 975 discloses a gel electrophoresis apparatus where the gel cassette is inclined between 5.degree. and 10.degree. relative to the vertical plane. The purpose of the inclination is to facilitate the handling of the apparatus in that the inclination prevents the gel cassette from tipping when it is being clamped to the electrophoresis apparatus. The above difficulty of clearly seeing the gel edge is neither mentioned nor overcome by means of this inclination.